|Publication number||US7149003 B2|
|Application number||US 09/858,312|
|Publication date||Dec 12, 2006|
|Filing date||May 15, 2001|
|Priority date||May 15, 2001|
|Also published as||DE10220351A1, US20020171877|
|Publication number||09858312, 858312, US 7149003 B2, US 7149003B2, US-B2-7149003, US7149003 B2, US7149003B2|
|Inventors||Paul K. Mui, Russell A. Mendenhall|
|Original Assignee||Hewlett-Packard Development Company, L.P.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (14), Non-Patent Citations (1), Referenced by (2), Classifications (13), Legal Events (7)|
|External Links: USPTO, USPTO Assignment, Espacenet|
1. Field of the Invention
The present invention relates generally to optical scanners and, more particularly to a method for bi-directional flatbed scanning and automatic document feed.
2. Background Art
Optical scanning and copying devices employ a method wherein data representative of a scanned object is produced by projecting an image of the scanned object onto an optical sensor. The optical scanning device may include scanner optics which may reduce the size of a projected image. The image of the scanned object is projected onto an optical sensor by linear increment by means of a moving scan line. The moving scan line is produced either by moving an image bearing media with respect to the scanner optical assembly or by moving the scanner optical assembly relative to an image bearing media. The optical sensor produce data representative of the intensity of the light projected thereon. These data may be digitized and stored on data storage media. Such stored data may be processed by a processing device to produce an image output or display.
Black and white or grayscale and some color optical scanning processes may require a single pass in order to acquire an image from which corresponding data is generated, processed and stored to produce an image of the object. Some color optical scanning processes require multiple passes in order to acquire multiple color component images from which corresponding data is generated and stored to produce a color image of the object. Typically data representative of red, green and blue component color images of the scanned object are produced and correlated for storage.
Various types of photosensor devices may be used in optical scanning devices. One such photosensor device is the charge coupled photosensor device or “CCD”. A CCD creates an electrical charge in response to exposure to light. The magnitude of the electrical charge created is dependent on the intensity and the duration of the light exposure.
In optical scanning devices CCD cells are aligned in linear arrays. Each cell has a portion of a scan line image projected thereon as the scan line sweeps across a scanned object. The charge in each of the cells is measured and discharged at a “sampling interval”. The direction parallel to the scan line movement relative to the object is the “scan direction”. A scanner linear photosensor array includes a set of cells aligned in a “cross linear array”, i.e. in a direction perpendicular to the scan direction. Each cell is defined by a width and a length, the width measured in the scan direction and the length measured in the cross linear direction. Scanners typically operate at a scanline sweep equal to one cell width per CCD sampling interval. At any time during a scanning operation, each cell in the CCD array includes an area that corresponds to an area of the object which is being imaged. This area of the CCD array is referred to herein as a “cross linear sampling”. The corresponding area of the scanned object is referred to herein as an “object linear segment”.
In flatbed optical scanning devices and copiers of the prior art, image bearing media is placed on a transparent platen and the carriage assembly scans the image from the top of the page to the bottom of the page while the image remains stationary on the transparent platen. When the top to bottom scan is complete, the carriage assembly returns to a top of the page position ready for the next top to bottom scan. In a black and white or one pass color scanning device, two traverses of the page length are required to scan a single image. In a multiple or three pass color scanning device, six traverses of the page length are required to scan a single image.
In a flatbed optical scanning device including an automatic document feed (ADF), image bearing media will be fed in repeated sequence for positioning on the flatbed for scanning and then on to an output document tray or document receiver. The carriage assembly repeatedly cycles from top to bottom and bottom to top scanning media in repeated sequence from the top of the page to the bottom of the page until such time as the ADF no longer contains media for feeding. The process repeats until the last image is scanned and then the carriage assembly returns to a top of the page position ready for the next scan job.
Processor operable image processing software processes digital data representative of the scanned image or images for storage, transmission, display, printing or other output.
It may be desirable to reduce the number of scanner carriage movement sequences by substantially 50 percent. It may be desirable to reduce scanning time by substantially 50 percent. It may also be desirable to increase the reliability of a scanning device by reducing total operation time for any given multi-page scanning task. It may also be desirable to improve long term scan and print quality by reducing the total mechanical stress over the life of the scanning device caused by vibration by reducing total operation time.
The present invention is directed to a method for scanning an object including the steps of moving a first scanline relative to the object in a top to bottom scan direction, i.e. from the top of an image bearing media to the bottom of the image bearing media, followed by moving a second scanline relative to the object in a bottom to top scan direction, i.e. from the bottom of an image bearing media to the top of the image bearing media. An optical scanning device for producing machine-readable data representative of an object includes a transport assembly for moving a scanline relative to the object in a top to bottom scan direction from the top of the object to the bottom of the object. The transport assembly is also configured for moving the scanline relative to the object in a bottom to top scan direction from the bottom of the object to the top of the object. The optical scanning device also includes an imaging assembly operable in successive sampling intervals for generating a plurality of cross linear samplings image data representative of the object and a processing device responsive to a signal indicating a scan direction for selectively indexing a plurality of cross linear samplings in either a forward sequential order or a reverse sequential order.
In one preferred embodiment of the invention, the method for scanning an image includes the steps of feeding a first image bearing media through an automatic document feeding device to a flatbed scanner. The media is positioned on a transparent platen and the media is scanned from the top of the media to the bottom of the media. Once the carriage assembly reaches a top to bottom scan direction limit, the first image bearing media is transported off the platen and a second image bearing media is positioned on the transparent platen. The second media is scanned from the bottom to the top of the media, i.e. in a bottom to top scan direction. This sequence may be repeated until such time as the ADF no longer contains media to feed, or until such time as a stop scan command is provided by the scanning device controller.
Processor operable image data processing software indexes data representative of successive cross linear sampling.
For those images scanned from the top to the bottom of the media, typically even odd numbered images, or odd numbered scanning passes, each successive “cross linear sampling” is forward indexed in sequential order, i.e. S1, S2, S3, . . . Sx, where S is a cross linear sampling from 1 through X. When compiled, the image data order replicates the object.
For those images scanned from the bottom of the media to the top of the media, typically even numbered images, or even numbered scanning passes, each successive “cross linear sampling” is reverse indexed in reverse sequential order, i.e. Sx, Sx-1, Sx-2, Sx-3, . . . S1, where S is a cross linear sampling from X through 1. Once again, when compiled, the image data order replicates the object.
The invention substantially reduces the number of scanner carriage movements and the scanning time. Since the scanner carriage movement is reduced, the reliability of the system is improved because of less wear and tear. It also reduces the vibration impact on the printing system because of reduced carriage movement which improves print quality.
As seen in
As seen in
Once carriage assembly 28 reaches bottom to top scan direction limit 37, second image bearing media 13B is transported off transparent platen 14 to receiver 19, a third image bearing media (not shown) is positioned on transparent platen 14 by operation of automatic document feeder 11 and the previously described sequence may be repeated until such time as controller 42 (shown in
As shown in
Scanning operations initiate once again at INITIATE SCAN 57. The controller senses the direction of carriage assembly movement at SENSE CARRIAGE DIRECTION 58, and a bottom to top scan direction is sensed at BOTTOM TO TOP SCAN DIRECTION 65. The scan/sampling process begins at BEGIN SAMPLING 66 and each successive cross linear sampling is reverse indexed at REVERSE INDEX CROSS LINEAR SAMPLINGS 67. When device controller senses the travel limit at SENSE CARRIAGE TRAVEL LIMIT 62, the controller queries the ADF to sense the presence of additional media for scanning at MEDIA PRESENT? 63. If media is not present, as indicated at NO 68, the process ends the scan operation at END SCAN 69.
While this invention has been described with reference to the detailed embodiments, this is not meant to be construed in a limiting sense. Various modifications to the described embodiments, as well as additional embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as fall within the true scope of the invention.
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|U.S. Classification||358/474, 358/498, 358/496, 358/497|
|International Classification||H04N1/04, H04N1/107, G03B27/50, H04N1/10|
|Cooperative Classification||H04N1/04, H04N2201/0462, H04N1/1017, H04N2201/0454|
|Aug 22, 2001||AS||Assignment|
Owner name: HEWLETT-PACKARD COMPANY, COLORADO
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MUI, PAUL K.;MENDENHALL, RUSSELL A.;REEL/FRAME:012098/0184;SIGNING DATES FROM 20010521 TO 20010601
|Sep 30, 2003||AS||Assignment|
Owner name: HEWLETT-PACKARD DEVELOPMENT COMPANY L.P.,TEXAS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HEWLETT-PACKARD COMPANY;REEL/FRAME:014061/0492
Effective date: 20030926
|May 5, 2009||CC||Certificate of correction|
|Jun 14, 2010||FPAY||Fee payment|
Year of fee payment: 4
|Jul 25, 2014||REMI||Maintenance fee reminder mailed|
|Dec 12, 2014||LAPS||Lapse for failure to pay maintenance fees|
|Feb 3, 2015||FP||Expired due to failure to pay maintenance fee|
Effective date: 20141212